Shaft Seal Assembly

ABSTRACT

An illustrative embodiment of a shaft seal assembly generally includes a fixed stator, a floating stator, and a sealing member. In the illustrative embodiment the fixed stator may be formed with one or more fluid conduits that are in fluid communication with one or fluid conduits formed in the floating stator. The fluid conduits in the floating stator may be in fluid communication with one or more fluid conduits formed in a sealing member. A rotational interface may exist between the sealing member and a shaft, and the various fluid conduits may be configured to create a fluid barrier at that interface. Other embodiments of a shaft seal assembly may create a fluid barrier at a rotational interface between a rotor and a floating stator.

CROSS REFERENCE TO RELATED APPLICATIONS

Applicant Inpro/Seal LLC, a limited liability company organized underthe laws of the state of Delaware and the United States of America,states that this application is a continuation of U.S. patentapplication Ser. No. 15/872,783, filed on Jan. 16, 2018, which is acontinuation of U.S. patent application Ser. No. 15/026,205 filed onMar. 30, 2016, which application was filed as an entry into the NationalPhase in the United States, claimed the filing benefit of, and was basedon PCT Patent Application assigned serial number PCT/US2014/058325,filed on Sep. 30, 2014, which claimed priority from provisional U.S.Pat. App. No. 61/884,880 filed on Sep. 30, 2013, all of which areincorporated by reference herein in their entireties.

FIELD OF THE INVENTION

The present invention relates to a shaft seal assembly with multipleembodiments. In certain embodiments, the shaft seal assembly may be usedas a product seal between a product vessel and a shaft therein.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

No federal funds were used to create or develop the invention herein.

REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTINGCOMPACT DISK APPENDIX

N/A

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the advantages of the invention will be readilyunderstood, a more particular description of the invention brieflydescribed above will be rendered by reference to specific embodimentsillustrated in the appended drawings. Understanding that these drawingsdepict only typical embodiments of the invention and are not thereforeto be considered limited of its scope, the invention will be describedand explained with additional specificity and detail through the use ofthe accompanying drawings.

FIG. 1 is a perspective exterior view of the shaft seal assembly.

FIG. 2 is an exterior end view of the shaft seal assembly with the shaftelement aligned.

FIG. 3 is a sectional view of a first embodiment of the shaft sealassembly, as shown in FIG. 2 and mounted to a housing.

FIG. 3A illustrates the first surface seal-shaft integrity duringangular and radial shaft alignment.

FIG. 3B illustrates second surface seal-shaft integrity during angularand radial shaft alignment.

FIG. 4 is an exterior end view with the shaft misaligned.

FIG. 5 is a sectional view of the first embodiment as shown in FIG. 3with both angular and radial misalignment of the shaft applied.

FIG. 5A illustrates first seal-shaft integrity allowed by articulationduring angular and radial shaft misalignment.

FIG. 5B illustrates second seal-shaft integrity allowed by articulationduring angular and radial shaft misalignment.

FIG. 6 is a sectional view of a second embodiment of the shaft sealassembly as shown in FIG. 2.

FIG. 7 is a sectional view of a third embodiment as shown in FIG. 2.

FIG. 8 is a perspective view of a fourth embodiment as mounted to avessel wall.

FIG. 9 is a cross-sectional view of a first embodiment of the pressurebalanced shaft seal assembly mounted to a housing wherein the shaft isin alignment.

FIG. 9A is a detailed view of the portion of the first embodiment of thepressure balanced shaft seal assembly adjacent the vent wherein theshaft is in alignment.

FIG. 9B is a detailed view of the portion of first embodiment of thepressure balanced shaft seal assembly adjacent the fluid return pathwaywherein the shaft is in alignment.

FIG. 10 is a cross-sectional view of the first embodiment of thepressure balanced shaft seal assembly shown during shaft misalignment.

FIG. 10A is a detailed view of the portion of the first embodiment ofthe pressure balanced shaft seal assembly adjacent the vent wherein theshaft is misaligned.

FIG. 10B is a detailed view of the portion of the first embodiment ofthe pressure balanced shaft seal assembly adjacent the fluid returnpathway wherein the shaft is misaligned.

FIG. 11 is a cross-sectional view of a second embodiment of the pressurebalanced shaft seal assembly wherein the shaft is in alignment.

FIG. 12 is a cross-sectional view of a third embodiment of the pressurebalanced shaft seal assembly wherein the shaft is in alignment.

FIG. 13 is a cross-sectional view of another embodiment of a bearingisolator (or shaft seal assembly) configured with a rotor.

FIG. 14 is a cross-sectional view of a portion of yet another embodimentof a bearing isolator (or shaft seal assembly) configured with a rotor.

FIG. 14A is a cross-sectional view of the portion of the embodiment of abearing isolator shown in FIG. 14 with the shaft misaligned and/orradially displaced.

FIG. 15 is a partial cross-sectional view of the embodiment of a bearingisolator shown in FIG. 13 wherein the shaft is misaligned and/orradially displaced.

FIG. 15A is a detailed view of a portion of the embodiment bearingisolator shown in FIG. 15.

FIG. 16A is an exterior face view of an illustrative embodiment of amulti-hole shaft seal assembly, wherein certain hidden surfaces areshown with broken lines.

FIG. 16B is a cross-sectional view of the embodiment of a multi-holeshaft seal assembly shown in FIG. 16A along line A-A.

FIG. 17A is an exterior face view of one embodiment of a sealing memberthat may be used with various embodiments of a multi-hole shaft sealassembly.

FIG. 17B is a cross-sectional view of the embodiment of a sealing membershown in FIG. 17A along line K-K.

DETAILED DESCRIPTION—ELEMENT LISTING (FIGS. 1-12)

Description Element No. Shaft  1 Fixed stator  2 Fixed stator(part-line)   2a Labyrinth seal  3 Radiused face   3a Floating stator  4Fluid return pathway  5 Shaft seal clearance  6 First o-ring  7Anti-rotation pin  8 Vent  9 Anti-rotation groove (floating stator) 10Spherical interface 11 Anti-rotation pin 12 Second o-ring 13 Labyrinthseal pattern grooves 14 First o-ring channel 15 Cavity for anti-rotationdevice (fixed stator) 16 Axial face of labyrinth seal 17 Axial face offloating stator 18 Second o-ring channel 19 First clearance betweenfloating stator/fixed stator 20 Second clearance between floatingstator/fixed stator 21 Throttle groove 22 Labyrinth pattern annulargroove 23 Sleeve 24 Shaft seal assembly 25 Throttle (alignment skate) 26Floating stator annular groove 27 Labyrinth seal passage 28 Floatingstator passage 29 Housing 30 Angle of misalignment 31 Bearings andbearing cavity 32 Mounting bolts 33 Vessel wall 34 Pressure balancedshaft seal assembly 40 Labyrinth seal interior face 42 Floating statorinterior face 44 Pressure balancing annular channel 46 First radialinterface  47a Second radial interface  47b Fixed stator annular groove48 Annular groove radial-interior surface  48a

DETAILED DESCRIPTION

Before the various embodiments of the present invention are explained indetail, it is to be understood that the invention is not limited in itsapplication to the details of construction and the arrangements ofcomponents set forth in the following description or illustrated in thedrawings. The invention is capable of other embodiments and of beingpracticed or of being carried out in various ways. Also, it is to beunderstood that phraseology and terminology used herein with referenceto device or element orientation (such as, for example, terms like“front”, “back”, “up”, “down”, “top”, “bottom”, and the like) are onlyused to simplify description of the present invention, and do not aloneindicate or imply that the device or element referred to must have aparticular orientation. In addition, terms such as “first”, “second”,and “third” are used herein and in the appended claims for purposes ofdescription and are not intended to indicate or imply relativeimportance or significance. Furthermore, any dimensions recited orcalled out herein are for exemplary purposes only and are not meant tolimit the scope of the present disclosure in any way unless so recitedin the claims.

FIGS. 1-5 provide various views of a first illustrative embodiment ofthe shaft seal assembly 25 that allows for sealing various lubricatingsolutions within bearing housing 30 and/or preventing ingress ofcontaminants to the housing 30, which may be configured as a bearinghousing. FIGS. 6 and 7 provide alternative illustrative embodiments ofthe shaft seal assembly 25 wherein sealing fluids are used. Applicantherein defines sealing fluids to include at least both liquids andvapors. Applicant considers air, nitrogen, water and steam as well asany other fluid that may work with the proposed shaft seal assembly toprovide a pressurized fluid barrier for any and all embodimentsdisclosed herein to be within the purview of the present disclosure. Thegas or fluid chosen may be based at least upon process suitability withthe product to be sealed.

FIG. 1 is a perspective exterior view of the first illustrativeembodiment of a shaft seal assembly 25 arranged and engaged with a shaft1 inserted through the fixed stator 2 of shaft seal assembly 25. FIG. 2is an exterior end view of the shaft seal assembly with shaft 1 alignedwithin the shaft seal assembly 25.

FIG. 3 is a sectional view of a first embodiment of the shaft sealassembly 25 shown in FIG. 2 illustrating that the shaft seal assembly 25may be configured as a labyrinth seal for retaining lubrication solutionwithin the bearing cavity 32 of housing 30 and/or preventing ingress ofcontaminants into the housing 30. The shaft 1 shown in FIG. 3 mayexperience radial, angular or axial movement relative to the fixedstator 2 or a portion thereof at various times. The fixed stator 2 ofthe shaft seal assembly 25 may be engaged with a housing 30 via anysuitable method and/or structure, including but not limited toflange-mounted or press-fit. The shaft seal assembly 25 may also be usedin applications with a rotating housing and stationary shaft. (Notshown) As required by the particular application of the shaft 1 and/orshaft seal assembly 25, the shaft 1 may be allowed to move freely in theaxial direction in relation to the shaft seal assembly 25.

A labyrinth seal 3 having an interior surface may be positioned adjacentshaft 1. A defined clearance 6 may exist between the interior surface ofsaid labyrinth seal 3 and the shaft 1. A radiused surface 3 a may beconfigured such that it is opposite the interior surface of thelabyrinth seal 3. The radiused surface 3 a of the labyrinth seal 3 andthe interior of the floating stator 4 may be configured to form aspherical interface 11. O-ring channels 15 and o-rings 7 may be disposedto cooperate with the radiused surface 3 a of the labyrinth seal 3 toseal (or trap) fluid migration through, between and along engagedlabyrinth seal 3 and floating stator 4 while maintaining a sphericalinterface 11, which spherical interface 11 may allow limited relativerotational movement (articulation) between labyrinth seal 3 and floatingstator 4.

O-ring channels 15, as shown, may be machined into the floating stator 4and may be positioned at the spherical interface 11 with labyrinth seal3. O-ring channels 15 may be configured such that they are annular andcontinuous in relation to labyrinth seal 3. The o-ring channel 15 ando-ring 7 may also be placed in the labyrinth seal 3 adjacent thespherical interface 11. In certain embodiments, o-rings 7 may beconstructed of materials that are compatible with both the product to besealed and the preferred sealing fluid. O-ring channels 15 and o-rings 7are but one possible combination of structures that may be used to sealvarious portions within the shaft seal assembly 25. Any other structuresand/or method suitable for the particular embodiment of a shaft sealassembly 25 may be used without limitation.

Strategically placed anti-rotation pin(s) 12 may be inserted intoanti-rotation grooves 10 and may serve to limit relative rotationalmovement between labyrinth seal 3 and floating stator 4. A plurality ofanti-rotation grooves 10 and pins 12 may be placed around the radius ofthe shaft 1. If the shaft seal assembly 25 is used in combination with asealing fluid, strategic anti-rotation pins 12 may be removed allowingcorresponding anti-rotation grooves 10 to serve as a fluid passagethrough vent 9 and lubricant return 5, one illustrative embodiment ofwhich is shown in FIG. 7. Additionally, the relationship of thediameters of anti-rotation pins 12 and anti-rotation grooves 10 may beselected to allow more or less angular misalignment of the shaft 1,respectively. For example, a relatively small-diameter anti-rotation pin12 used with a large-diameter anti-rotation groove 10 would allow forgreater relative movement of the labyrinth seal 3 in relation to thefloating stator 4 in response to angular misalignment of shaft 1. Alabyrinth seal 3 is one possible embodiment of a sealing structure thatmay be used adjacent to the shaft 1 within the shaft seal assembly 25.However, other structures and/or methods may be used to achieve similarfunctionality without limitation.

An annular channel may be formed within fixed stator 2 and may bedefined by clearance 20 and 21 as allowed between the exterior of saidfloating stator 4 and the interior of the fixed stator 2 of shaft sealassembly 25. The annular channel of fixed stator 2 is highlighted asA-A′ in FIG. 2. The annular channel of the fixed stator 2 may be formedwith interior surfaces that are configured such that they aresubstantially perpendicular to said shaft 1. The exterior surfaces ofthe floating stator 4, which may be substantially encompassed within theannular channel of the fixed stator 2, may cooperatively engage with thefirst and second interior perpendicular faces of the fixed stator 2. Aninner interface may be formed by the first (shaft seal assembly 25inboard side) perpendicular annular channel surface of the fixed stator2 engaging with the first (inboard side) perpendicular face of thefloating stator 4. An outer interface may be formed by the second (shaftseal assembly 25 outboard side) perpendicular annular interior channelsurface of the fixed stator 2 engaging with the second (outboard side)perpendicular face of the floating stator 4. O-ring channels 19 ando-rings 13 may be disposed therein and may cooperate with the surfacesof floating stator 4 that are in perpendicular to relation to shaft 1.These o-rings 13 may function to seal (or trap) fluid migration betweenand along engaged floating stator 4 while allowing limited relativerotational movement between floating stator 4 and fixed stator 2.Floating stator 4 and fixed stator 2 are one possible embodiment ofcooperatively engaged portions of a shaft seal assembly 25 that may beconfigured to allow relative motion between the portions in at least onedimension, and which may be used in combination with labyrinth seal 3within the shaft seal assembly 25. However, other structures and/ormethods may be used to achieve similar functionality without limitation.

O-ring channels 19 may be configured such that they are annular andcontinuous in relation to shaft 1. In an embodiment not shown herein,the o-ring channels 19 and o-rings 13 may be placed in the body of thefloating stator 4 rather than the fixed stator 2. It is contemplatedthat for many applications it may be optimal to place those o-ringchannels 19 and corresponding o-rings 13 in similar proximal relation.In certain embodiments, o-rings 7 may be constructed of materials thatare compatible with both the product to be sealed and the preferredsealing fluid. O-ring channels 15 and o-rings 7 are but one possiblecombination of structures that may be used to seal various portionswithin the shaft seal assembly 25. Any other structures and/or methodsuitable for the particular embodiment of a shaft seal assembly 25 maybe used without limitation.

Strategically placed anti-rotation pin(s) 8 may be inserted intoanti-rotation groove(s) 16 and may serve to limit both relative radialand rotational movement between floating stator 4 and interior side offixed stator 2. A plurality of anti-rotation grooves 16 and pins 8 maybe placed around the radius of the shaft 1. The relationship of thediameters of anti-rotation pins 8 and anti-rotation grooves 16 may alsobe selected to allow more or less angular misalignment of the shaft. Forexample, a small-diameter anti-rotation pin 8 and large-diameter fixedstator anti-rotation groove may allow for greater relative movement ofthe labyrinth seal 3 in response to angular misalignment of shaft 1.

The labyrinth pattern seal grooves 14 may be pressure equalized byventing through one or more vents 9. If so desired, the vents 9 may besupplied with a pressurized sealing fluid such that the sealing fluidover-pressurizes the labyrinth area 14 and shaft seal clearance 6 toincrease the efficacy of shaft seal assembly 25. A spherical interface11 between the labyrinth seal 3 and the floating stator 4 may beconfigured to allow for angular misalignment between the shaft 1 andfixed stator 2. O-ring channels 19 are annular with the shaft 1 and, asshown, may be machined into the fixed stator 2 and positioned at theinterface between the fixed stator 2 and floating stator 4. O-ringchannel 19 may also be placed in the floating stator 4 and may beengaged with o-rings 13, which may be configured to provide sealingcontact with the fixed stator 2.

FIG. 3A illustrates seal-shaft integrity during angular and radial shaft1 alignment. This view highlights the alignment of the axial face 17 ofthe labyrinth seal 3 and the axial face 18 of the floating stator 4.Particular focus is drawn to the alignment of the axial faces 17, 18 atthe spherical interface 11 between the floating stator 4 and labyrinth3. FIG. 3B illustrates the shaft-seal integrity during angular andradial shaft 1 alignment at the surface opposite that shown in FIG. 3A.This view highlights the alignment of the axial faces 17, 18 oflabyrinth seal 3 and floating stator 4, respectively, for the oppositeportion of the shaft seal assembly 25 as shown in FIG. 3A. Those ofordinary skill in the art will appreciate that because the shaft 1 andthe illustrative embodiments of a shaft seal assembly 25 are of acircular shape and nature, the surfaces are shown 360 degrees aroundshaft 1. Again, particular focus is drawn to the alignment of the axialfaces 17, 18 at the spherical interface 11 between the labyrinth seal 3and floating stator 4. FIGS. 3A and 3B also illustrate the first definedclearance 20 between the floating stator 4 and the fixed stator 2 andthe second defined clearance 21 between the floating stator 4 and fixedstator 2 and opposite the first defined clearance 20.

In FIGS. 2, 3, 3A and 3B, the shaft 1 is not experiencing radial,angular or axial movement with respect to a housing 30. Accordingly, inthe illustrative embodiments the width of the defined clearances 20 and21, which may be substantially equal, may indicate little movement ormisalignment upon the floating stator 4.

FIG. 4 is an exterior end view of the shaft seal assembly 25 with therotatable shaft 1 misaligned therein. FIG. 5 is a sectional view of thefirst embodiment of the shaft seal assembly 25 as shown in FIG. 3 withboth angular and radial misalignment of the shaft 1 applied. The shaft 1as shown in FIG. 5 is also of the type that may experience radial,angular or axial movement relative to the fixed stator 2 (and/or housing30) of the shaft seal assembly 25.

As shown at FIG. 5, the defined radial clearance 6 of labyrinth seal 3with shaft 1 may be maintained even though the angle of shaftmisalignment 31 has changed. The shaft 1 still may be allowed to movefreely in the axial direction even though the angle of shaftmisalignment 31 has changed. The arrangement of the shaft seal assembly25 may allow the labyrinth seal 3 to move with the floating stator 4upon introduction of radial movement of said shaft 1.

The labyrinth seal 3 and floating stator 4 may be secured together byone or more compressed o-rings 7 or any other suitable structure and/ormethod. Rotation of the labyrinth seal 3 within the floating stator 4may be prevented by anti-rotation members, which may include but are notlimited to screws, anti-rotation pins 8, or similar devices to inhibitrotation. The pins as shown in FIGS. 3, 3A, 3B, 5, 6 and 7 are onestructure for preventing rotation of the labyrinth seal 3 and floatingstator 4. However, any other suitable structure and/or method may beused to achieve similar results without limitation.

Lubricant, sealing fluid, or other media may be collected and drainedthrough a series of one or more optional drains or lubricant returnpathways 5. The labyrinth seal 3 may be pressure-equalized by ventingthrough one or more vents 9. If so desired, the vents 9 may be suppliedwith pressurized air or other gas or fluid media to over-pressurize thelabyrinth seal 3 to increase seal efficacy. The combination of closetolerances between the cooperatively engaged mechanical portions of theshaft seal assembly 25 and pressurized sealing fluid may inhibit bothproduct and contaminant contact with the internals of the shaft sealassembly 25. The spherical interface 11 between the labyrinth seal 3 andthe floating stator 4 may be configured to allow for angularmisalignment between the shaft 1 and fixed stator 2. O-ring channel 19and o-ring 13, which may be disposed therein, may cooperate with theopposing faces of the floating stator 4, which may be configured suchthat they are substantially in perpendicular relation to the rotationalaxis of the shaft 1. In this manner, the o-rings 13 may cooperate withthe floating stator 4 to seal (or trap) fluid migration between andalong the floating stator 4 while allowing relative radial movementbetween stator 4 and fixed stator 2.

FIG. 5A illustrates seal-shaft integrity allowed by the shaft sealassembly 25 during angular and radial shaft 1 misalignment. This viewhighlights the offset or articulation of the axial faces 17 of thelabyrinth seal 3 may have in relation the axial faces 18 of the floatingstator 4 for a first portion of the shaft seal assembly 25. Particularfocus is drawn to the offset of the axial faces 17, 18 at the sphericalinterface 11 between labyrinth seal 3 and floating stator 4.

FIG. 5B illustrates seal-shaft integrity for a second surface, oppositethe first surface shown in FIG. 5A, during angular and radial shaftmisalignment. This view highlights that during misalignment of shaft 1,axial faces 17, 18, of the labyrinth seal 3 and floating stator 4,respectively, may not be aligned but instead move (articulate) inrelation to each other. The shaft-to-seal clearance 6 may be maintainedin response to the shaft 1 misalignment and the overall seal integritymay not be compromised because the seal integrity of the floating stator4 to fixed stator 2 and the floating stator 4 to labyrinth seal 3 may bemaintained during shaft 1 misalignment. Those of ordinary skill in theart will appreciate that because the shaft 1 and shaft seal assembly 25may be circular in shape and nature, the surfaces are shown 360 degreesaround shaft 1. FIGS. 5A and 5B also illustrate the first clearance orgap 20 between the floating stator 4 and the fixed stator 2 and thesecond clearance or gap 21 between the floating stator 4 and fixedstator 2 and opposite the first clearance or gap 20 during relativemovement (other than rotational) between the shaft 1 and the housing 30.

In FIGS. 4, 5, 5A and 5B, the shaft 1 is experiencing radial, angular,or axial movement during rotation of the shaft 1 and the width of thegaps or clearances 20, 21 are shown as having changed in response tothat movement as compared to the gaps or clearances 20, 21 depicted inFIGS. 3, 3A and 3B. The change in dimensions of clearance 20, 21indicate the floating stator 4 may move in response to the movement orangular misalignment of shaft 1. The shaft seal assembly 25 may allowarticulation between axial faces 17, 18, maintenance of sphericalinterface 11 and radial movement at first and second clearance, 20, 21,respectively, while maintaining shaft seal clearance 6.

FIG. 6 is a sectional view of a second embodiment of the shaft sealassembly 25 as shown in FIG. 2 for over-pressurization with alternativelabyrinth seal pattern grooves 14. In this embodiment, the labyrinthseal pattern grooves 14 may be comprised of a friction-reducingsubstance such as polytetrafluoroethylene (PTFE), wherein thefriction-reducing substance may be configured such that it forms a closeclearance to the shaft 1. PTFE is also sometimes referred to as Teflon®,which is manufactured and marketed by Dupont. PTFE is a plastic withhigh chemical resistance, low and high temperature capability,resistance to weathering, low friction, electrical and thermalinsulation, and high lubricity. Carbon or any other materials withoutlimitation may be substituted for PTFE to provide the necessary sealingqualities and lubricous qualities for labyrinth seal pattern grooves 14.

Pressurized sealing fluids may be supplied to over-pressurize thelubricious labyrinth pattern 26 as shown in FIG. 6. The pressurizedsealing fluids may be introduced to the annular groove 23 of thethrottle 26 through one or more inlets. Throttle 26 may also be referredto as “an alignment skate” by those of ordinary skill in the art.Throttle 26 may allow the labyrinth seal 3 to respond to movement of theshaft 1 caused by the misalignment of the shaft 1. The pressurizedsealing fluid may pass through the close clearance formed between theshaft 1 and labyrinth seal 3 having throttle 26. The close proximity ofthe throttle 26 to the shaft 1 also may create resistance to the sealingfluid flow over the shaft 1 and may cause pressure to build up insidethe annular groove 23. Floating annular groove 27 in cooperation andconnection with annular groove 23 also may provide an outlet for excesssealing fluid to be bled out of shaft seal assembly 25 for pressureequalization or to maintain a continuous fluid purge on the shaftsealing assembly 25 during operation. An advantage afforded by thisaspect of the shaft sealing assembly 25 is its application wherein“clean-in place” product-seal decontamination procedures are preferredor required. Examples would include food grade applications.

FIG. 7 illustrates shaft seal assembly 25 with the anti-rotation pin 12removed to improve visualization of the inlets. These would typically becomprised of, but are not limited to, a series of ports, inlets orpassages about the circumference of the shaft seal assembly 25. FIG. 7also illustrates that the shape and pattern of the labyrinth seal 3 maybe varied from one embodiment of the shaft seal assembly 25 to the next.The shape of throttles 26 may also be varied as shown by the squareprofile shown at throttle groove 22 in addition to the circular-type 26.Also note that where direct contact with the shaft 1 is not desired, theshaft seal assembly 25 may be used in combination with a separate sleeve24 that would be attached by varied means to the shaft 1.

FIG. 8 shows that another embodiment of the shaft seal assembly 25wherein the shaft seal assembly 25 has been affixed to a vessel wall 34.The shaft seal assembly 25 may be affixed to vessel wall 34 throughsecurement members (e.g., including but not limited to mounting bolts33) to ensure improved sealing wherein shaft 1 is subjected to angularmisalignment. The mounting bolts 33 and slots (not numbered) through theshaft seal assembly 25 exterior are one structure and method of mountingthe shaft seal assembly 25 to a housing 30. However, any suitablestructure and/or method may be used without limitation.

In certain applications, especially those wherein the process side ofshaft seal assembly 25 (generally the area to the left of the shaft sealassembly 25 as shown in FIGS. 3-3B and 5-7) is at an increased pressure,it is desirable for the shaft seal assembly 25 to be configured tobalance the pressure experienced by the shaft seal assembly 25 in theaxial direction. A pressure balanced shaft seal assembly 40 thatbalances the pressure (in the axial direction) that the product appliesto the labyrinth seal interior face 42 and floating stator interior face44 is shown in FIGS. 9-12.

In the first embodiment of the pressure balanced shaft seal assembly asshown in FIGS. 9-10B, the shaft sealing member (i.e., the labyrinth seal3 in combination with the floating stator 4) includes a pressurebalancing annular channel 46. Save for the pressure balancing annularchannel 46, the pressure balanced shaft seal assembly 40 may operate ingenerally the same manner as the shaft seal assembly 25 shown in FIGS.1-8 and described in detail above. That is, the floating stator 4 may bepositioned in the fixed stator annular groove 48. The first clearancebetween floating stator/fixed stator 20, which in the embodimentspictured herein may be between the floating stator radial-exteriorsurface 45 and the annular groove radial-interior surface 48 a (shown inFIGS. 9A and 9B), may account at least for radial perturbations of theshaft 1 with respect to the housing 30. The spherical interface 11between the floating stator 4 and the labyrinth seal 3 may account atleast for angular perturbations of the shaft 1 with respect to thehousing 30.

The pressure balancing annular channel 46 may be formed in the floatingstator 4 adjacent the first radial interface 47 a between the floatingstator 4 and the fixed stator 2, as shown in FIGS. 9-10 for the firstembodiment. As shown in the various embodiments pictured herein, thefirst radial interface 47 a between the floating stator 4 and the fixedstator 2 may be adjacent the portion of the fixed stator 2 fashionedwith the cavity for anti-rotation device 16. That is, the axial face ofthe floating stator 4 that is positioned within the fixed stator 2 andfurthest from the process side of the pressure balanced shaft sealassembly 40. A second radial interface 47 b between the floating stator4 and fixed stator 2, which may be substantially parallel to the firstradial interface 47 a, may be positioned closer to the process side ofthe pressure balanced shaft seal assembly 40 as compared to the firstradial interface 47 a.

In many applications the optimal radial dimension of the pressurebalancing annular channel 46 may be substantially similar to the radialdimension of the floating stator interior face 44 so that the area ofthe floating stator 4 acted upon by the product and the area of thefloating stator 4 acted upon by the sealing fluid may have relativelyequal surface areas. In such a configuration, the axial forces maygenerally balance if the product and the sealing fluid are pressurizedto approximately the same value. Accordingly, the optimal radialdimension of the pressure balancing annular channel 46 may depend on thedesign characteristics of the entire system, and the radial dimension ofthe pressure balancing annular channel 46 may be any suitable amount fora particular application, whether greater or less than the radialdimension of the floating stator interior face 44. The axial dimensionof the pressure balancing annular channel 46 may also vary depending onthe design characteristics of the entire system, including but notlimited to the specific sealing fluid that is used, the productpressure, and the pressure of the sealing fluid. In some applicationsthe optimal axial dimension of the pressure balancing annular channel 46will be 0.005 of an inch, but may be greater in other embodiments andless in still other embodiments.

The pressure balancing annular channel 46 may allow sealing fluidintroduced into the first clearance between floating stator/fixed stator20 (from where the sealing fluid may enter the pressure balancingannular channel 46) to act upon the floating stator 4 in an axialdirection. Typically, the process side of the pressure balanced shaftseal assembly 40 (generally the area to the left of the pressurebalanced shaft seal assembly 40 as shown in FIGS. 9-12) experiencesforces from the process fluid acting upon the labyrinth seal interiorface 42 and floating stator interior face 44. These forces are mostoften due to the pressure generated by the rotating equipment to whichthe shaft 1 is coupled. For example, if the shaft 1 is coupled to afluid pump generating seventy pounds per square inch (psi) of headpressure, the process side of the pressure balanced shaft seal assembly40 may be pressurized to approximately 70 psi. This pressurized fluidmay act upon the labyrinth seal interior face 42 and floating statorinterior face 44, and consequently urge the labyrinth seal 3 andfloating stator 4 in the axial direction away from the process side ofthe pressure balancing shaft seal assembly 40 (i.e., generally to theright side of the drawing as depicted in FIGS. 9-12). By contrast,sealing fluid located in the pressure balancing annular channel 46 mayurge the labyrinth seal 3 and floating stator 4 in the axial directiontoward the process side of the pressure balancing shaft seal assembly40, which may substantially cancel the axial force the product exertsupon the pressure balancing shaft seal assembly 40, depending on thedesign of the sealing fluid system.

FIGS. 11 and 12 show a second and third embodiment of the pressurebalanced shaft seal assembly 40, respectively. The second and thirdembodiments of the pressure balanced shaft seal assembly 40 generallycorrespond to the second and third embodiments of the shaft sealassembly 25 as shown in FIGS. 7 and 8 and described in detail above.However, as with the first embodiment of the pressure balanced shaftseal assembly 40 as shown in FIGS. 9-10B, the second and thirdembodiments include a pressure balancing annular channel 46.

The various embodiments of the pressure balanced shaft seal assembly 40pictured and described herein may be formed with a fixed stator 2 andfloating stator 4 that may be comprised of two distinct portions. Theseembodiments may facilitate assembly of the pressure balanced shaft sealassembly 40 since in the embodiments pictured herein the majority of thefloating stator 4 may be positioned within the fixed stator 2. Wheninstalling a pressure balanced shaft seal assembly 40 according to thefirst embodiment (as pictured in FIGS. 9-10B), the first portion offixed stator 2 (i.e., the portion adjacent the process side of thepressure balanced shaft seal assembly 40) may be affixed to a housing30. Next, the floating stator 4 and labyrinth seal 3 may be positionedas a singular assembled piece (wherein the components forming thespherical interface 11 have been preassembled) between the shaft 1 andthe first portion of the fixed stator 2. The placement of the floatingstator 4 and labyrinth seal 3 within the fixed stator 3 may forms thesecond axial interface 47 b between the fixed stator 2 and floatingstator 4. Finally, the second portion of the fixed stator 2 (i.e., theportion furthest from the process side of the pressure balanced shaftseal assembly 40) may be positioned adjacent to and affixed to the firstportion of the fixed stator 2. The positioning of the second portion ofthe fixed stator 2 subsequently may form the first radial interface 47 abetween the fixed stator 2 and floating stator 4.

Alternatively, the floating stator 4 and labyrinth seal 3 may beseparately positioned within the fixed stator annular groove 48. Forexample, after the first portion of the fixed stator 2 has been affixedto the housing 30, the first portion of the floating stator 4 may bepositioned within the fixed stator annular groove 48. The placement ofthe first portion of the floating stator 4 within the fixed statorannular groove 48 may form the second axial interface 47 b between thefixed stator 2 and floating stator 4. Next, the labyrinth seal 3 may bepositioned adjacent the shaft 3, the placement of which may form aportion of the spherical interface 11 between the floating stator 4 andlabyrinth seal 3. Next, the second portion of the floating stator 4 maybe positioned adjacent the first portion of the floating stator 4 andaffixed thereto with a plurality of anti-rotation pins 8, which maycomplete the spherical interface 11 between the floating stator 4 andlabyrinth seal 3. Finally, the second portion of the fixed stator 2 maybe affixed to the first portion of the fixed stator 2 with a pluralityof bolts, rivets, or other fasteners without limitation, the placementof which may form the first axial interface 47 a between the floatingstator 4 and fixed stator 2. Any suitable securing members known tothose skilled in the art may be used to affix the first and secondportions of the floating stator 4 to one another or to affix the firstand second portions of the fixed stator 2 to one another in anyembodiments of a shaft seal assembly 25 or pressure balanced shaft sealassembly 40 without limitation.

ELEMENT LISTING (FIGS. 13-15A)

Description Element No. Shaft  10 Bearing isolator  18 Housing  19 Rotor 20 Stator 30, 31a Fixed stator  31 Passage 40, 40a Spherical surface50, 51 Clearance  52 Frictional seal  60 Flange unit   61a Center point 80 Conduit  99 Fluid 100 Pin 101 Annular recess 102

FIG. 13 shows another embodiment of a bearing isolator 18 (or shaft sealassembly) mounted adjacent a shaft 10. The shaft 10 may extend throughthe bearing isolator 18 and/or the housing 19. A source of gas or fluid,100 which may include but is not limited water, gas, vapor and/orlubricant, may also be in communication with the bearing isolator 18 viaconduit 99. The rotor 20 may be affixed to the shaft 10 by means by africtional seal 60, which may be configured as one or more o-rings. Therotor 20 may be configured to follow the rotational movement of theshaft 10 because of the frictional engagement of the seals 60. Thepassages 40 and 40 a may be configured as shown but will not bedescribed in detail here because such description is already understoodby those of ordinary skill in the art.

A pair of corresponding spherical surfaces 50 and 51 may be used tocreate a self-aligning radial clearance 52 between the rotor 20 and thestator 30 prior to, during, and after use. This clearance 52 may bemaintained at a constant value even as the shaft 10 becomes misalignedduring use. Various amounts and direction of misalignment between thecenterline of the shaft 10 and the housing 19 are illustrated in FIGS.15-17. An annular recess 102 between the stator 30 and fixed stator 31may allow the bearing isolator 18 to accommodate a predetermined amountof radial shaft displacement.

In the embodiments shown herein, the spherical surfaces 50, 51 may havea center point identical from the axial faces of both the rotor andstator 20, 30, respectively. However, the spherical surfaces 50, 51 maybe radially, and/or as shown, vertically spaced apart. These sphericalsurfaces 50, 51 may move radially in response to and/or in connectionwith and/or in concert with the radially positioning of other componentsof the bearing isolator 18. Typically, if the shaft 10 becomesmisaligned with respect to the housing 19, the rotor 20 may consequentlybecome misaligned with respect thereto, and then the spherical surfaces50, 51 and/or the stator 30, moving radially within the annular recessof the fixed stator 31, may compensate for the misalignment.

FIGS. 15 and 15A illustrate that in one embodiment of the bearingisolator 18, the rotor 20 may move with respect to the stator 30, 31 asshaft 10 is misaligned with respect to housing 19 through theinteraction between spherical surfaces 50, 51. Such relative movement tohelp to ensure the distances between the center points of the rotor 20and stator 30 and a fixed point on the housing 19 are constant orrelatively constant during use.

In the embodiment of the bearing isolator 18 shown in FIGS. 14 and 14A,the spherical surfaces 50, 51 may be positioned on a fixed stator 31 andstator 31 a, respectively, rather than on the rotor 20 and stator 30.Still referring to FIGS. 14 and 14A, this design may allow the rotor 20and stator 31 a to move with respect to the fixed stator 31, flange unit61 a, and/or housing 19. The rotor 20, stator 31 a, and fixed stator 31may move radially with respect to the flange unit 61 a (and consequentlywith respect to the housing 19) as best shown in FIG. 14A. In thisembodiment of the bearing isolator 18 there may be a very minimal amountof relative rotation between the spherical surfaces 50, 51.

The embodiment of the bearing isolator 18 shown in FIGS. 14 and 14A mayprovide for controlled radial movement of the fixed stator 31, stator 31a, and/or rotor 20 with respect to flange unit 61 a, which flange unit61 a may be engaged with a housing 19. Rotational movement of the fixedstator 30 with respect to the flange unit 61 a may be prevented byanti-rotational pins 101. The fixed stator 31 may be frictionallysecured to the flange unit 61 a using a frictional seal 61, which may bemade of any material with sufficient elasticity and frictionalcharacteristics to hold the fixed stator 31 in a fixed radial positionwith respect to the flange unit 61 a but still be responsive to theradial forces when the shaft 10 is misaligned. Changes to the radialposition of the fixed stator 31, stator 31 a, and/or rotor 20 and theresulting positions thereof (as well as the resulting position of theinterface between the fixed stator 31 and stator 31 a) may occur untilthe radial force is fully accommodated or until the maximum radialdisplacement of the bearing isolator 18 is reached.

Referring now to FIGS. 15 and 15A, in operation the rotor 20 may bemoved radially as the shaft 10 becomes misaligned with respect to thehousing 19. Radial movement of the spherical surfaces 50, 51 between thestator 31 a and fixed stator 31 may result from this pressure. FIG. 15shows potential resultant radial movement of center point 80 as theshaft 10 is misaligned. During normal operation, the shaft 10 istypically horizontal with respect to the orientation shown in FIG. 15,as represented by line A. As the shaft 10 becomes misaligned in a mannerrepresented by line B, the center point 80 may move to a point alongline A″. As the shaft 10 becomes misaligned in a manner represented byline B′, the center point 80 may move to a point along line A′. However,in other shaft 10 misalignments, the radial positions of the rotor 20,stator 30, and/or fixed stator 31 may be constant and the sphericalsurfaces 50, 51 may compensate for the shaft 10 misalignment. From thepreceding description it will be apparent that the bearing isolator 18may provide a constant seal around the shaft 10 because the distancebetween the spherical surfaces 50, 51 may be maintained as a constantregardless of shaft 10 misalignment of a normal or design nature.

The physical dimensions of the spherical surfaces 50 and 51 may vary inlinear value and in distance from the center point 80, depending on thespecific application of the bearing isolator 18. These variations willbe utilized to accommodate different sizes of shafts and seals anddifferent amounts of misalignment, and therefore in no way limit thescope of the bearing isolator 18 as disclosed herein. Additionally, andsuitable structure and/or method for engaging various elements with oneanother either rotationally, fixedly, or with various degrees of freedomof motion therebetween may be used with the shaft seal assembly 18without limitation, including but not limited to screws, bolts, pins,chemical adhesives, interference fits, and/or combinations thereof.

ELEMENT LISTING (FIGS. 16-17)

Description Element No. Shaft seal assembly 10 Shaft 12 Fastener 14Fixed stator 20 Fixed stator seal groove  20a Main body 21 Face plate 22Face plate pin recess  22a Face plate seal groove  22b Inlet 24 Annularrecess 26 Seal 28 Floating stator 30 Floating stator seal groove  30aRadial exterior surface 32 First pin recess 33 Pin 34 Second pin recess35 Second pin recess enlarged portion  35a Floating stator annulargroove 37 Concave surface 38 Sealing member 40 Recess 42 Radial bore 44Radial bore inlet  44a Radial bore outlet  44b Radial interior surface46 Convex surface 48

Another embodiment of a shaft seal assembly 10 is shown in FIGS. 16A &16B. This embodiment is similar to the embodiment of the shaft sealassembly 25 described above and shown in FIGS. 1-12. The shaft sealassembly 10 may include a fixed stator 20, floating stator 30, and asealing member 40, as shown. In the pictured embodiment, the sealingmember 40 may be positioned adjacent a shaft 12 that is rotatable withrespect to the shaft seal assembly 10 and/or housing. Accordingly, arotational interface may exist between a radial interior surface 46 ofthe sealing member 40 positioned adjacent the shaft 12 and an exteriorportion of the shaft 12. In other embodiments of the shaft seal assembly10 not pictured herein, the sealing member 40 may be engaged with theshaft 12 such that it rotates therewith (e.g., the shaft seal assembly10 may be configured with a rotor). In such an embodiment, a rotationalinterface may exist between a concave surface 38 of the floating stator30 and a convex surface 48 of the sealing member 40. Accordingly, thescope of the shaft seal assembly 10 as disclosed herein extends to shaftseal assemblies 10 in which the sealing member 40 does or does notrotate with a shaft 12.

The embodiment of the shaft seal assembly 10 shown in FIGS. 16A & 16Bmay include a fixed stator 20 that may be securely mounted to a housing(not shown in FIGS. 16A & 16B) by any suitable methods and/or structure.The fixed stator 20 may include a main body 21 and a face plate 22 thatmay be engaged with one another via one or more fasteners 14. It iscontemplated that a fixed stator 20 formed with a main body 21 and faceplate 22 may facilitate ease of installation of the shaft seal assembly10 in certain applications. In such applications, the main body 21 maybe affixed to the housing, the sealing member 40 and floating stator 30may be positioned appropriately, and then the face plate 22 may besecured to the main body 21. However, the scope of the presentdisclosure is in no way limited by the specific mounting and/orinstallation method of the shaft seal assembly 10.

The fixed stator 20 may be formed with an annular recess 26 into which aportion of the floating stator 30 and/or sealing member 40 may bepositioned. A predetermined clearance between the radial exteriorsurface 32 of the floating stator 30 (as well as the axial exteriorsurfaces thereof) and the interior surfaces of the annular recess 26 maybe selected to allow for a predetermined amount of relative radialand/or axial movement between the fixed stator 20 and floating stator30. At least one pin 34 (which may be radially oriented as in theembodiment shown in FIGS. 16A & 16B) may be engaged with the floatingstator 30 at a second pin recess 35, and a portion of the pin 34 mayextend into a recess 42 formed in the sealing member 40. Additionally,other pins (not shown, but which may be axially oriented) also may beengaged with the floating stator about a first pin recess 33, and aportion of that pin may extend into a face plate pin recess 22 a. In theillustrative embodiment shown in FIGS. 16A & 16B, the pins 35 maymitigate relative rotation between the floating stator 30 and thesealing member 40. Axially oriented pins (not shown) may mitigaterelative rotation between the floating stator 30 and the fixed stator20. The axial interfaces between the floating stator 30 and fixed stator20 may be sealed with seals 28, which seals 28 may be positioned infixed stator seal grooves 20 a and/or face plate seal grooves 22 b. Theseals 28 may be configured as o-rings, but may be differently configuredin other embodiments of the shaft seal assembly 10 without limitation.

The floating stator 30 may also be formed with a concave surface 38 in aradial interior portion thereof. This concave surface 38 may form asemi-spherical interface with a corresponding convex surface 48 formedin the radial exterior portion of the sealing member 40. Accordingly,the shaft seal assembly 10 shown in FIGS. 16A & 16B may accommodateshaft 12 misalignment, shaft 12 radial movement, and shaft 12 axialmovement with respect to the shaft seal assembly 10 and/or equipmenthousing in an identical and/or similar manner to that previouslydescribed for the shaft seal assemblies 25 shown in FIGS. 1-12.

The illustrative embodiment of the shaft seal assembly 10 also mayinclude various fluid conduits for applying a sealing fluid to the shaftseal assembly 10. The fixed stator 20 may be formed with one or moreinlets 24 for introduction of a sealing fluid to the shaft seal assembly10. The inlet 24 may be in fluid communication with the annular recess26 formed in the fixed stator 20, which annular recess 26 may be influid communication with one or more radial passages (not shown) formedin the floating stator 30 and extending from the radial exterior surface32 thereof to the concave surface 38 thereof. Alternatively, or inaddition to the one or more radial passages, the second pin recess 35formed in the floating stator 30 may be configured to allow a specificamount of sealing fluid to traverse the length of the second pin recess35 in a radially inward direction. The radially interior terminus of thesecond pin recess 35 may be formed with a second pin recess enlargedportion 35 a. Alternatively, the floating stator 30 may be formed with afloating stator annular groove 37 on the concave surface 38 thereof.These radial passages, second pin recess 35, second pin recess enlargedportion 35 a, and/or floating stator annular groove 37 may serve as aconduit for sealing fluid from the annular recess 26 of the fixed stator20 to the convex surface 48 of the sealing member 40. Accordingly, thescope of the shaft seal assembly 10 is not limited by the specificcombinations of fluid conduits disclosed herein, but extends to allconfigurations of fluid conduits that may supply a sealing fluid to thesealing member 40.

The fixed stator 20 and/or seals 28 between the fixed stator 20 andfloating stator 30 may be configured so that the majority of sealingfluid introduced to the inlet 24 passes through the floating stator 30(by any fluid conduit configuration, as explained above) in a radiallyinward direction. The semi-spherical interface between the floatingstator 30 concave surface 38 and the sealing member 40 convex surface 48may be sealed with seals 28, which seals 28 may be positioned infloating stator seal grooves 30 a and/or sealing member seal grooves(not shown). The seals 28 may be configured as o-rings, but any suitablestructure and/or method may be used without limitation. The floatingstator 30, sealing member 40, and/or seals 28 therebetween may beconfigured so that the majority of sealing fluid exiting the floatingstator 30 passes through the sealing member 40 through a plurality ofradial bores 44 in a direction from the convex surface 48 of the sealingmember 40 to the radial interior surface 46 thereof (i.e., in agenerally radially inward direction, such that the sealing fluid exitsthe shaft seal assembly 10 adjacent the shaft 12).

The fixed stator 20, floating stator 30, and/or sealing member 40 may beconfigured such that the fluid conduits formed therein allow themajority of sealing fluid to exit the shaft seal assembly 10 from anarea between the sealing member 40 and shaft 12 at a predetermined ratefor a given set of operation parameters (e.g., sealing fluid viscosity,pressure, and/or volumetric flow rate, rpm of shaft 12, etc.). Theillustrative embodiment of the shaft seal assembly 10 may be formed withthirty two (32) radial bores 44 in the sealing member 40 incorresponding pairs equally spaced about the circumference of thesealing member, which is best shown in FIGS. 17A & 17B. Each radial bore44 may be formed with a radial bore inlet 44 a adjacent the convexsurface 48 and a radial bore outlet 44 b adjacent the radial interiorsurface 46. However, in other embodiments of the sealing member 40 notshown herein, the sealing member 40 may be configured with differentlyconfigured radial bores 44, different numbers of radial bores 44, and/ordifferent relative positions of radial bores 44 without limitation.

It is contemplated that the configuration of radial bores 44 shown inthe embodiment of a sealing member 40 pictured in FIGS. 17A and 17B maybe more efficient than other configurations in that a lower volumetricflow rate of sealing fluid may be required for a given set ofoperational parameters when compared to the prior art. Additionally, thesmooth, generally cylindrical configuration of the radial interiorsurface 46 may create a pressurized fluid barrier between the shaft 12and the sealing member 40 at the interface thereof (e.g., a “lift-off”seal). This may lead to a nearly frictionless shaft seal assembly 10with no and/or minimal contact between the shaft 12 and the sealingmember 40 during operation. However, in other embodiments, differentnumbers, spacing, and/or configurations of the fluid conduits in thefixed stator 20, floating stator 30, and/or sealing member 40 may beused without departing from the spirit and scope of the shaft sealassembly 10 as disclosed and claimed herein.

In light of the present disclosure, it will be apparent to those skilledin the art that the configuration of fluid conduits disclosed herein maybe adapted to create a pressurized fluid barrier between any interfaceat which two elements are rotating with respect to one another, such asthe articulated seal disclosed in U.S. Pat. No. 7,090,403. U.S. Pat. No.7,090,403 is incorporated by reference herein in its entirety, anddiscloses embodiments of a shaft seal assembly having a sphericalrotational interface between a rotor and a floating stator (such asthose shown in FIGS. 13, 15, and 15A) and embodiments of a shaft sealassembly having a generally non-rotating spherical interface between twoportions of a stator (such as those shown in FIGS. 14 and 14A).Accordingly, the scope of the shaft seal assembly 10 as disclosed hereinis not limited by the location and/or type of rotational interface theshaft seal assembly 10 is configured to accommodate.

For example, in an embodiment not pictured herein, the stator 30 of anembodiment similar to that shown in FIGS. 13, 15, and 15A may beconfigured with one or more generally narrow diameter radial bores(which may be generally similar to those shown in the embodiment inFIGS. 17A and 17B). Those radial bores may be configured so as toprovide fluid from an external source (which may be in fluidcommunication with passage 40) to the interface between sphericalsurfaces on the stator portions 31, 31 a (which may be configured as aconcave surface on stator 31 and a convex surface on stator 31 a).Alternatively, the stator 31 may be configured with radial bores thatserve to provide fluid from an external source (which may be in fluidcommunication with passage 40) to the interface between stator 31 a androtor 20, which may be a rotational interface having a labyrinth sealpattern and/or one or more seals (which may be configured as o-rings)therein.

The specific configuration and/or physical dimensions of the variousfeatures of the fixed stator 20, floating stator 30, and/or sealingmember 40 (e.g., the radial dimension of the annular recess 26, thesurface area of the concave surface 38 and/or convex surface 48, thediameter, length, and orientation of the radial bores 44, etc.) may varydepending on the specific application of the shaft seal assembly 10.These variations may be utilized to accommodate different sizes ofshafts 12 and/or shaft seal assemblies 10 and different amounts and/ortypes of relative movement between a shaft 12 and shaft seal assembly10.

The materials used to construct the shaft seal assemblies 10, 25 andvarious elements thereof will vary depending on the specificapplication, but it is contemplated that bronze, brass, stainless steel,or other non-sparking metals and/or metallic alloys and/or combinationsthereof will be especially useful for some applications. Accordingly,the above-referenced elements may be constructed of any material knownto those skilled in the art or later developed, which material isappropriate for the specific application of the shaft seal assembly 10,25, without departing from the spirit and scope of the shaft sealassemblies 10, 25 as disclosed and claimed herein.

Having described the preferred embodiments, other features of the shaftseal assemblies 10, 25 will undoubtedly occur to those of ordinary skillin the art, as will numerous modifications and alterations in theembodiments as illustrated herein, all of which may be achieved withoutdeparting from the spirit and scope of the shaft seal assemblies 10, 25disclosed herein. Accordingly, the methods and embodiments pictured anddescribed herein are for illustrative purposes only.

It should be noted that the shaft seal assemblies 10, 25 are not limitedto the specific embodiments pictured and described herein, but areintended to apply to all similar apparatuses and methods foraccommodating shaft(s) misalignment with respect to a housing and/orshaft seal assembly 10, 25, whether the misalignment is angular, radial,and/or axial; and for configuring a shaft seal assembly 10 to create apressurized fluid barrier between a rotating element and a non-rotatingelement. Modifications and alterations from the described embodimentswill occur to those skilled in the art without departure from the spiritand scope of the shaft seal assemblies 10, 25.

What is claimed is:
 1. A shaft seal assembly comprising: a first statorhaving a concave surface on a radially interior portion thereof; asecond stator positioned within the first stator, the second statorhaving a convex surface on a radially exterior portion thereof anddefining a channel on a radially interior surface thereof; and athrottle positioned within the channel of the second stator, thethrottle being moveable in at least a radial dimension with respect tothe first stator and the second stator, wherein the concave surface ofthe first stator and the convex surface of the second stator form asemispherical interface between the first stator and the second stator.2. The shaft seal assembly of claim 1, wherein the first statorcomprises an inlet extending from a radially exterior surface of thefirst stator to the concave surface of the first stator.
 3. The shaftseal assembly of claim 2, further comprising a pressurized sealing fluidin fluid communication with the inlet of the first stator.
 4. The shaftseal assembly of claim 1, further comprising a face plate selectivelyengageable with an axially oriented surface of the second stator.
 5. Theshaft seal assembly of claim 1, wherein the second stator comprises aradial passage extending from a radially exterior surface of the secondstator to a radially exterior portion thereof.
 6. The shaft sealassembly of claim 1, wherein the second stator comprises a main body,and the channel is formed in a portion of the main body.
 7. The shaftseal assembly of claim 1, wherein the concave surface of the firststator defines an annular recess.
 8. The shaft seal assembly of claim 1,wherein the throttle comprises a radial channel extending from aradially exterior surface of the throttle to a radially interior surfaceof the throttle.
 9. The shaft assembly of claim 1, wherein the firststator comprises one or more pin recesses receiving one or more pinsthat limit a degree of angular misalignment between the first stator andthe second stator.